docs: def add_thing(self, name, location, **kwargs):
          """Create a Thing, set its location,
          and set its initial attributes from the keyword arguments (if
          any).
  
          """
          if name in self.thing:
              raise WorldIntegrityError(
                  "Already have a Thing named {}".format(name)
              )
          self.add_node(name, **kwargs)
          if isinstance(location, Node):
              location = location.name
          self.place2thing(name, location,)